{"id":168489,"date":"2024-11-06T12:48:18","date_gmt":"2024-11-06T04:48:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168489\/"},"modified":"2024-11-06T12:48:19","modified_gmt":"2024-11-06T04:48:19","slug":"sql-%e4%b8%ad-alter-%e7%9a%84%e4%bd%bf%e7%94%a8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168489\/","title":{"rendered":"SQL \u4e2d ALTER \u7684\u4f7f\u7528"},"content":{"rendered":"<h1 id=\"sql-%e4%b8%ad-alter-%e7%9a%84%e4%bd%bf%e7%94%a8-nGNBxWvOpJ\">SQL \u4e2d ALTER \u7684\u4f7f\u7528<\/h1>\n<p>\u5728 SQL \u4e2d\uff0cALTER \u8a9e\u53e5\u662f\u4e00\u500b\u975e\u5e38\u91cd\u8981\u7684\u547d\u4ee4\uff0c\u4e3b\u8981\u7528\u65bc\u4fee\u6539\u8cc7\u6599\u5eab\u4e2d\u7684\u73fe\u6709\u8cc7\u6599\u8868\u7d50\u69cb\u3002\u7121\u8ad6\u662f\u6dfb\u52a0\u3001\u522a\u9664\u9084\u662f\u4fee\u6539\u8cc7\u6599\u8868\u4e2d\u7684\u6b04\u4f4d\uff0cALTER \u90fd\u80fd\u5920\u63d0\u4f9b\u9748\u6d3b\u7684\u89e3\u6c7a\u65b9\u6848\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e ALTER \u8a9e\u53e5\u7684\u4f7f\u7528\u65b9\u6cd5\u53ca\u5176\u61c9\u7528\u7bc4\u4f8b\u3002<\/p>\n<h2 id=\"alter-%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-nGNBxWvOpJ\">ALTER \u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>ALTER \u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>ALTER TABLE table_name\n    {ADD column_name datatype [constraint],\n    | DROP COLUMN column_name,\n    | MODIFY COLUMN column_name datatype [constraint]};\n<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>table_name<\/code> \u662f\u8981\u4fee\u6539\u7684\u8cc7\u6599\u8868\u540d\u7a31\uff0c<code>column_name<\/code> \u662f\u8981\u6dfb\u52a0\u3001\u522a\u9664\u6216\u4fee\u6539\u7684\u6b04\u4f4d\u540d\u7a31\uff0c<code>datatype<\/code> \u5247\u662f\u6b04\u4f4d\u7684\u6578\u64da\u985e\u578b\uff0c<code>constraint<\/code> \u662f\u53ef\u9078\u7684\u7d04\u675f\u689d\u4ef6\u3002<\/p>\n<h2 id=\"%e6%b7%bb%e5%8a%a0%e6%ac%84%e4%bd%8d-nGNBxWvOpJ\">\u6dfb\u52a0\u6b04\u4f4d<\/h2>\n<p>\u4f7f\u7528 ALTER \u8a9e\u53e5\u6dfb\u52a0\u6b04\u4f4d\u7684\u7bc4\u4f8b\u5982\u4e0b\uff1a<\/p>\n<pre><code>ALTER TABLE employees\nADD birthdate DATE;\n<\/code><\/pre>\n<p>\u4e0a\u8ff0\u8a9e\u53e5\u5c07\u5728 <code>employees<\/code> \u8cc7\u6599\u8868\u4e2d\u6dfb\u52a0\u4e00\u500b\u540d\u70ba <code>birthdate<\/code> \u7684\u65b0\u6b04\u4f4d\uff0c\u6578\u64da\u985e\u578b\u70ba\u65e5\u671f\u3002<\/p>\n<h2 id=\"%e5%88%aa%e9%99%a4%e6%ac%84%e4%bd%8d-nGNBxWvOpJ\">\u522a\u9664\u6b04\u4f4d<\/h2>\n<p>\u5982\u679c\u9700\u8981\u522a\u9664\u8cc7\u6599\u8868\u4e2d\u7684\u67d0\u500b\u6b04\u4f4d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>ALTER TABLE employees\nDROP COLUMN birthdate;\n<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u5f9e <code>employees<\/code> \u8cc7\u6599\u8868\u4e2d\u522a\u9664 <code>birthdate<\/code> \u6b04\u4f4d\u3002<\/p>\n<h2 id=\"%e4%bf%ae%e6%94%b9%e6%ac%84%e4%bd%8d-nGNBxWvOpJ\">\u4fee\u6539\u6b04\u4f4d<\/h2>\n<p>ALTER \u8a9e\u53e5\u9084\u53ef\u4ee5\u7528\u4f86\u4fee\u6539\u73fe\u6709\u6b04\u4f4d\u7684\u6578\u64da\u985e\u578b\u6216\u7d04\u675f\u689d\u4ef6\u3002\u4ee5\u4e0b\u662f\u4fee\u6539\u6b04\u4f4d\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>ALTER TABLE employees\nMODIFY COLUMN salary DECIMAL(10, 2) NOT NULL;\n<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07 <code>employees<\/code> \u8cc7\u6599\u8868\u4e2d\u7684 <code>salary<\/code> \u6b04\u4f4d\u7684\u6578\u64da\u985e\u578b\u4fee\u6539\u70ba\u5341\u9032\u5236\uff0c\u4e26\u8a2d\u7f6e\u70ba\u4e0d\u5141\u8a31\u70ba\u7a7a\u3002<\/p>\n<h2 id=\"%e9%87%8d%e5%91%bd%e5%90%8d%e6%ac%84%e4%bd%8d-nGNBxWvOpJ\">\u91cd\u547d\u540d\u6b04\u4f4d<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u60a8\u53ef\u80fd\u9700\u8981\u91cd\u547d\u540d\u8cc7\u6599\u8868\u4e2d\u7684\u6b04\u4f4d\u3002\u9019\u53ef\u4ee5\u901a\u904e\u4ee5\u4e0b\u8a9e\u6cd5\u5be6\u73fe\uff1a<\/p>\n<pre><code>ALTER TABLE employees\nRENAME COLUMN old_name TO new_name;\n<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07 <code>employees<\/code> \u8cc7\u6599\u8868\u4e2d\u7684 <code>old_name<\/code> \u6b04\u4f4d\u91cd\u547d\u540d\u70ba <code>new_name<\/code>\u3002<\/p>\n<h2 id=\"%e9%87%8d%e5%91%bd%e5%90%8d%e8%b3%87%e6%96%99%e8%a1%a8-nGNBxWvOpJ\">\u91cd\u547d\u540d\u8cc7\u6599\u8868<\/h2>\n<p>\u9664\u4e86\u4fee\u6539\u6b04\u4f4d\uff0cALTER \u8a9e\u53e5\u9084\u53ef\u4ee5\u7528\u4f86\u91cd\u547d\u540d\u6574\u500b\u8cc7\u6599\u8868\u3002\u4ee5\u4e0b\u662f\u91cd\u547d\u540d\u8cc7\u6599\u8868\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>ALTER TABLE old_table_name\nRENAME TO new_table_name;\n<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8cc7\u6599\u8868 <code>old_table_name<\/code> \u91cd\u547d\u540d\u70ba <code>new_table_name<\/code>\u3002<\/p>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-nGNBxWvOpJ\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528 ALTER \u8a9e\u53e5\u6642\uff0c\u6709\u5e7e\u9ede\u9700\u8981\u7279\u5225\u6ce8\u610f\uff1a<\/p>\n<ul>\n<li>\u5728\u9032\u884c\u7d50\u69cb\u4fee\u6539\u4e4b\u524d\uff0c\u5efa\u8b70\u5099\u4efd\u8cc7\u6599\u8868\uff0c\u4ee5\u9632\u6b62\u6578\u64da\u4e1f\u5931\u3002<\/li>\n<li>\u67d0\u4e9b\u8cc7\u6599\u5eab\u7cfb\u7d71\u5c0d\u65bc ALTER \u8a9e\u53e5\u7684\u652f\u6301\u7a0b\u5ea6\u4e0d\u540c\uff0c\u5177\u9ad4\u8a9e\u6cd5\u53ef\u80fd\u6703\u6709\u6240\u5dee\u7570\u3002<\/li>\n<li>\u5728\u4fee\u6539\u8cc7\u6599\u8868\u7d50\u69cb\u6642\uff0c\u53ef\u80fd\u6703\u5f71\u97ff\u5230\u73fe\u6709\u7684\u61c9\u7528\u7a0b\u5f0f\uff0c\u56e0\u6b64\u9700\u8981\u8b39\u614e\u64cd\u4f5c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-nGNBxWvOpJ\">\u7e3d\u7d50<\/h2>\n<p>ALTER \u8a9e\u53e5\u5728 SQL \u4e2d\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u9748\u6d3b\u5730\u4fee\u6539\u8cc7\u6599\u8868\u7d50\u69cb\u3002\u7121\u8ad6\u662f\u6dfb\u52a0\u3001\u522a\u9664\u9084\u662f\u4fee\u6539\u6b04\u4f4d\uff0c\u6b63\u78ba\u4f7f\u7528 ALTER \u8a9e\u53e5\u90fd\u80fd\u63d0\u9ad8\u8cc7\u6599\u5eab\u7684\u7ba1\u7406\u6548\u7387\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u7ba1\u7406\u8cc7\u6599\u5eab\u7684\u7528\u6236\u4f86\u8aaa\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2f VPS<\/a> \u670d\u52d9\u53ef\u4ee5\u63d0\u4f9b\u66f4\u597d\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\uff0c\u9032\u4e00\u6b65\u63d0\u5347\u8cc7\u6599\u5eab\u7684\u904b\u884c\u6548\u7387\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3 SQL \u4e2d ALTER \u7684\u4f7f\u7528\uff0c\u638c\u63e1\u5982\u4f55\u4fee\u6539\u6570\u636e\u5e93\u8868\u7ed3\u6784\u3001\u6dfb\u52a0\u5b57\u6bb5\u3001\u5220\u9664\u5b57\u6bb5\u53ca\u66f4\u6539\u6570\u636e\u7c7b\u578b\u7684\u6280\u5de7\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-168489","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168489","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=168489"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168489\/revisions"}],"predecessor-version":[{"id":168490,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168489\/revisions\/168490"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168489"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168489"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168489"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}